In Book 4 of Virgil’s Aeneid, I find two noteworthy phrases. First, in Virgil’s description of the monstrous goddess Rumor (lines 173–183; tr. Goold) —

At once Rumor runs through Libya’s great cities — Rumor, the swiftest of all evils. Speed lends her strength, and she wins vigour as she goes; small at first through fear, soon she mounts up to heaven and walks the ground with head hidden in the clouds.

Mother Earth, provoked to anger against the gods, brought her forth last, they say, as sister to Coeus and Enceladus, swift of foot and fleet of wing, a monster awful and huge, who for the many feathers in her body has as many watchful eyes beneath — mirabile dictu — as many tongues, as many sounding mouths, as many pricked-up ears.

Here “swift of foot and fleet of wing” translates pedibus celerem et pernicibus alis, where pernicibus is a form of the Latin adjective pernix “nimble.” I said to myself, “I’ve often heard of a pernicious rumor, but I always thought the word had more to do with its nipping viciousness than its mere speed!”

Well, it turns out that Latin pernix is indeed only a false cognate to English pernicious. The English word derives (via Latin pernicies) from per- “thoroughly” (as in perchlorate, an ion in which the central chlorine atom is even more thoroughly oxidized than in ordinary chlorate) + necō “kill” (as in Homo Necans): Something pernicious thoroughly kills or destroys. But I wonder if Virgil had both words (pernix and pernicies) in mind when composing this line.

The critics are more than willing to credit Virgil with virtuosic double-meanings in other places. For example, Clifford Weber, “Some Double Entendres in Ovid and Vergil” (Classical Philology 85.3, July 1990), points to Aeneid IV.80–83:

Then when all have gone their ways, and in turn the dim moon sinks her light and the falling stars invite sleep, alone she mourns in the empty hall and falls on the couch he has left.

In Latin this is:

Post ubi digressi, lumenque obscura vicissim
luna premit suadentque cadentia sidera somnos,
sola domo maeret vacua stratisque relictis
incubat.

Weber writes: “The sun and moon are particularly relevant to the Vergilian drama of Dido and Aeneas, in which the Phoenician queen is associated with the moon, the Trojan king with the sun […] Thus, at the beginning of line 82, Vergil predisposes his reader to assume momentarily that sol- belongs to a form of sol. [But in fact here it’s a form of solus ‘solitary.’] As Dido ‘grieves alone [sole] in the empty house [domo vacua],’ the meaning with sole still hovers in the background: ‘in the sunless house she grieves.’ The ‘sunless house’ par excellence is, of course, the underworld,” where Dido arrives at the end of Book 4.

Incidentally, while Virgil describes Rumor herself in Aeneid 4, Ovid very poetically describes Rumor’s house in Metamorphoses 12, right before the “little Iliad” which precedes his “little Aeneid.” (This is just one small instance of Ovid’s program of alluding to Virgil while not trying to compete with him head-to-head on any specific episode.) The house of Rumor, says Ovid, is set at the confluence of sea, land, and sky, atop a high mountain. It has a thousand entrances, but no doors; and it is all of sounding brass. Crowds fill the halls, murmuring, each adding to the tale he carries. In this way Rumor herself sees everything that happens in the heavens, in the ocean, and on land; and she inquires about everything too.

In line 81, quoted above, we hear that suadent cadentia sidera somnos, “the descending stars counsel sleep.” This phrase is euphonious: Ingo Gildenhard writes, “In the speedy opening part, the vowel piano in cadentia sidera (a-e-i-a-[i]-e-a) reflects the quickly falling stars and acts as foil to the heavy ‘os’ in somnos,” citing also R. G. Austin (1963): “Note the varied vowels, the repeated s sounds, the gentle assonance of suadentque cadentia […] The rhythm itself suggests sleep.” In fact the phrase is so appealing that this is the second time Virgil has used it: the first time was at II.9.

[…] Et iam nox umida caelo
praecipitat suadentque cadentia sidera somnos.

(“And now dewy night is speeding from the sky and the falling stars counsel sleep.”)

This phrase is puzzling at first glance: Surely the night stars are always up there — they don’t “set” like the sun! That is, individual stars and constellations may disappear below the horizon, but other stars rise to replace them. The only way we experience a sky without stars is if it’s overcast, or if the stars have been washed out by the rising sun.

Some translators and critics take the latter way out, translating cadentia as “fading” or “receding.” J. W. Mackail, in “Notes on Aeneid VIII” (The Classical Review 32.5/6, September 1918), writes:

Much confusion would have been saved, here and elsewhere, by realising that surgere and cadere as used of the stars by Virgil have not only their astronomical meaning of rising and setting, but that of appearance and disappearance with the end and beginning of daylight. Cadere may in such passages be translated “to pale,” and surgere “to shine out.” Thus the cadentia sidera of Aen. II.9 and IV.81 are the paling stars. […] Compare Milton’s

The stars grow high,
But night sits monarch yet in the mid sky;

where there is a different image for the same phenomenon, the fading or paling of the stars before dawn being pictured — which is what in fact it looks like — as their retreat to a greater distance.

I can’t speak for Milton, but it’s pretty clear that Virgil isn’t talking about the stars fading at sunrise. Sunrise is the time to wake, not the time to sleep! George Gifford’s “A Note on Dante and Virgil” (Italica 35.2, June 1958) persuasively gives the correct interpretation:

In Inferno VII.98–99, [Dante’s guide] Virgil urges against delay [using] a similar formula:

Già ogni stella cade che saliva / Quando mi mossi,
[“Already sinks each star that was ascending / When I set out”]

where the meaning clearly is, “six hours or more of our journey have elapsed; it is now past midnight.” We may infer, therefore, that Dante took Aeneas to mean “it is past midnight.” In this view, the “stars” referred to are the constellations associated with the present season, because they are visible in the earlier hours of darkness, which are normally waking hours. After midnight all of such stars as are visible will be setting in the west, or will at least have passed the zenith. They are in this sense cadentia sidera, wheeling downward in the sky.

Note that the “constellations associated with the present season” are those opposite what we think of as your “star sign.” If you’re born in May you’re “a Taurus,” but that’s because the sun is in Taurus, which means Taurus is invisible — it’s the constellations roughly opposite Taurus that are considered “spring constellations” in the stargazing sense. Ursa Major, for example, peaks in the sky around 10pm tonight, and Virgo around 11pm. (All seasons and times Northern Hemisphere–specific.) So when Virgo and Ursa Major are “falling,” says Virgil, it’s the right time for sleep.